newsticker-retrieval-interval

newsticker-retrieval-interval is a variable defined in `newst-backend.el'.
Its value is

3600

Documentation:
Time interval for retrieving new news items (seconds).
If this value is not positive (i.e. less than or equal to 0)
items are retrieved only once!
Please note that some feeds, e.g. Slashdot, will ban you if you
make it less than 1800 seconds (30 minutes)!

You can customize this variable.